He was returned as MP for the fifth time, taking the safe seat with 19,055 votes.

Mr Donaldson said it was a "good-natured" campaign after increasing his majority by more than 2,500 from 2010.

And, of course, there was rapturous applause and celebration from the DUP camp as they cheered their stalwart along to another Westminster triumph.

While the Lagan Valley count happened just metres away from the centre's pool and water park, there were no choppy waters or slippery slides for Donaldson, as the 52-year-old's ballot papers began piling up on to a second table.

Then, as the clock turned 1.30am and the second or third coffees were finished, his win was revealed to chants of "number one" from the party's cheerleaders.

"This is an important election, not just for Lagan Valley and for Northern Ireland, but it's an important election for the UK," Mr Donaldson said.

"And I believe the DUP and our unionist allies will be in a very important position at the end of this election."

Finishing second was Ulster Unionist Alexander Redpath on 6,055, who paid tribute to his DUP opponent.

He said the campaign was "very clean, good and all in great spirit".

Meanwhile, Trevor Lunn of Alliance was another winner on the night with a 32% increase in the party's vote. SDLP man Pat Catney received 2,500 votes, with Ukip's Alan Love on 2,200, the latter being seen as a triumph by the party's Northern Ireland leader David McNarry.

And despite the Conservatives' surprise performance in Britain, Tory candidate Helen Osborne - currently a councillor across the water in Winchester in the south of England - only managed 654 votes. That was fewer than Independent Jonny Orr - a man who once dressed as Darth Vader - who managed to rack uo 756 votes in the constituency.

Throughout the evening there was a gaggle of DUP heavyweights - including Paul Givan, Jonathan Craig and former Health Minister Edwin Poots - confidently observing the count floor and live television streams coming in.

Of course, when Mr Donaldson's name and boosted majority were announced to the crowd of politicians, reporters and supporters present, the room erupted.

It had been smooth sailing for the Lagan Valley count, with ballot boxes landing in the leisure centre shortly after 10pm.

There was a bit of hustle and bustle as candidates and staff packed around the tables with clipboards in hand.

Following his win, Mr Donaldson said: "I am delighted with the result in Lagan Valley. My vote has gone up, my majority has increased, but we take nothing for granted."